DENVER (CBS4) – Hail that hit the Denver area hard during another round of thunderstorms Wednesday night caused numerous problems at Denver International Airport, including damage to planes and dozens of flight cancellations.

Hail as large as 3/4 inches in diameter fell at the airport, damaging 18 planes, according to DIA.

An image of a plane at DIA with damage from Wednesday night's storm. A piece of luggage flew up in the air and hit the wing of this plane. (credit: DIA)

The hail, which fell for about 15 minutes, caused majors delays for travelers. About 1,000 people spent the night at the airport, although airport administrators didn’t enact the stranded passenger plan.

The Associated Press reported that Gov. Scott Walker of Wisconsin was among the passengers who wound up having to sleep on the floor.

United told the AP that they canceled 80 flights. Frontier Airlines canceled about 30 flights Thursday morning. Frontier Airlines spokesman Peter Kowalchuk said at 9 a.m. they might be forced to cancel more.

“We are in in process of examining all our aircraft,” Kowalchuk told CBS4. “We know we have at this point in time fewer than a dozen damaged. Right now eight to 10 is the preliminary count. We’re sending them off to repair.”

Kowalchuk said that even if the only damage to a plane is denting from a hailstone, flight regulations require that the plane not fly until it is fully inspected.

Hailstones that fell at DIA Wednesday night (credit: DIA)

There were other reports of damage at the airport, including to operator vehicles and passenger cars.